根据浏览器窗口大小自动缩放图片

转自http://www.oschina.net/code/snippet_54371_8165

(function($){

    $.fn.resizeimage = function(){

        var imgLoad = function (url, callback) {

            var img = new Image();

            img.src = url;

            if (img.complete) {

                callback(img.width, img.height);

            } else {

                img.onload = function () {

                    callback(img.width, img.height);

                    img.onload = null;

                };

            };

        };

        var original = {

            width:$(window).width()

        };

        return this.each(function(i,dom){

            var image = $(this);

            imgLoad(image.attr('src'),function(){

                var img = {

                    width:image.width(),

                    height:image.height()

                },percentage=1;

                if(img.width<original.width){

                    percentage = 1;

                }else{

                    percentage = (original.width)/img.width;

                }

                image.width(img.w=img.width*percentage-30).height(img.h=img.height*percentage);

                $(window).resize(function(){

                    var w = $(this).width();

                    percentage = w/img.width>1?1:w/img.width;

                    var newWidth = img.width*percentage-30;

                    var newHeight = img.height*percentage;

                    image.width(newWidth).height(newHeight);

                });

            });

        });

    };

})(jQuery);

使用方法:$('img').resizeimage();